


Don't you know there's part of me that longs to go

by justelaura



Category: Shadowhunters (TV)
Genre: F/F, Heline, No regret, TW: Mention of death, i broke my rules for you, let's leave and break an ancient curse together because why the hell not, lowkey an enemy to lovers au i guess, mermaid au, mermaid!aline, sapphic mermaids!!, shsapphicficathon
Language: English
Status: Completed
Published: 2020-01-05
Updated: 2020-01-05
Packaged: 2021-02-27 12:35:06
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,438
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22137151
Author URL: https://archiveofourown.org/users/justelaura/pseuds/justelaura
Summary: Long black hair and mesmerizing brown eyes, she was the definition of breathtaking. Her tail was deep blue with purple glints when the sun was reflected off it. Helen was so fascinated she almost forgot why she went there in the first place. She snapped out of her contemplation and realized why the mermaid was almost out of the water, so far away from her natural habitat. A net was restraining all the mermaid's movements and the latter was struggling to break free.
Relationships: Helen Blackthorn/Aline Penhallow
Comments: 1
Kudos: 10
Collections: shadowhunters sapphic ficathon, shadowhunters sapphic library





	Don't you know there's part of me that longs to go

**Author's Note:**

> For the fifth week of the shadowhunter sapphic ficathon, I offer you some sapphic mermaids!  
> Ok, I'm a little late and I missed the deadline but I just couldn't stop writing this fic... which was supposed to be short... oops
> 
> Prompt: I broke for rules for you + no regret
> 
> trigger warning:
> 
> *death and murder: mention of humans hunting and killing mermaids + brief description of how Lilith's son was killed
> 
> Enjoy!

> _I've had my adventure_
> 
> _I don't need something new_
> 
> _I'm afraid of what I'm risking_
> 
> _If I follow you_
> 
> _Into the unknown – Idina Menzel_

Alicante was a gorgeous and prosperous island. The land was so fertile and the sea so full of fish, the locals never knew drought or hunger.

The island was known for being a quiet place where you could live peacefully. But one day, something extraordinary happened. The sailors came back overexcited and said over and over that they had seen a mermaid. At first, the villagers just thought the sun hit too hard that day because if there were really mermaids in the sea, they would've seen them sooner. But then more mermaids were noticed in the following days by several people.

Years then decades passed and mermaids were still there. And so the locals decided that the reason why these mythical creatures suddenly appeared didn't matter.

A lot of stories were told about the mermaids living in the sea surrounding the island. Their tears could heal wounds, their songs could appease the mind, their blood could bring eternal youth to anyone who would taste it. Most of these legends were unfounded, but a lot of people believed in them deeply. And that's how it all started.

Mermaids hunters.

The fascination the humans had for mermaids had turned into an obsession, a wicked desire to possess their powers and steal what wasn't theirs. People started to reward anyone who would catch and kill a mermaid.

The most famous family of hunters was the Blackthorns and the number of mermaids they had caught in the last decades was impressive. Proud of this heritage, the parents wished to keep that legacy going. Every member of the family was highly trained but, everyone's hopes were turned towards the oldest child, Helen, who just celebrated her eighteenth birthday.

In theory, she knew how to drive a ship and how to catch a mermaid but she's never done it. Her parents had considered the sea too dangerous for an adolescent, but now that Helen was officially an adult, she would finally go on her very first hunt.

Helen dreaded that moment.

She's always been told that she was a warrior, that it was in her blood. This instinct to hunt was in her.

But was it, really?

Helen didn't think she would be able to do it. But she had to, she couldn't bring shame to her family. They were all counting on her. How could she let them down?

Helen sighed deeply.

Trying to avoid her family and also her responsibilities, she had invented an excuse and left home. She went for a walk and without realizing it, ended up at the beach. _Of course, I did..._

She sat on the warm sand and looked at the sea. The water was gorgeous and sailing a ship with this landscape was certainly breathtaking, Helen had no doubt. She wanted to go. But not for hunting. She wanted to explore the world. But she couldn't. She didn't need adventures. She needed to make her family proud.

Her eyes lowered to the knife she'd been holding this whole time. It was a birthday gift from her mother. This blade was the one her mother had used for on first hunt. And now Helen owned this weapon.

And she didn't know what to think.

Her siblings had looked at the knife with stars in their eyes, but when Helen was observing it, she just felt empty. The idea of using this weapon made her stomach twist in a very strange way.

She wasn't a killer.

Helen stood up. Staying unmoving was just making everything worse because she couldn't stop thinking. She needed to walk. And so she did.

She had been walking for ten minutes when she heard some noises. Like something or someone was hitting the water.

Helen thought someone was drowning so she ran toward the water, adrenaline flowing through her veins. She was expecting to see a kid who had moved too far out to sea and who didn't know how to come back. She was not expecting to see a mermaid.

Long black hair and mesmerizing brown eyes, she was the definition of breathtaking. Her tail was deep blue with purple glints when the sun was reflected off it. Helen was so fascinated she almost forgot why she went there in the first place. She snapped out of her contemplation and realized why the mermaid was almost out of the water, so far away from her natural habitat. A net was restraining all the mermaid's movements and the latter was struggling to break free.

The knife felt so heavy in Helen's hand. She held her breath. She wasn't a killer.

_But that's what I should do...That's what they would want..._

Helen tried to slow down her breathing.

_But what about what I want?_

She closed her eyes. Took a deep breath. Opened her eyes again and met the mermaid's gaze.

_I am not a killer._

Helen walked slowly, trying to not scare the mermaid, but the latter had stopped moving like she knew Helen wasn't an enemy.

_But I am your enemy. How can you trust me?_

Helen kneeled down beside the mermaid who was following all of her moves. Helen suddenly felt very weak and she bit her lips, resisting the urge to just look at the gorgeous woman who was so, so close to her.

“Stop doing that.” She said between her teeth.

The mermaid looked confused. “Doing what?”

Helen frowned. “I can't help you if you're hypnotizing me at the same time.”

“I'm not doing anything, I promise.”

 _Then why am I feeling so overwhelmed?_ Helen remained silent and cut the ropes one by one. She was almost done when the mermaid spoke again.

“I'm Aline.”

Aline. Helen liked the way it sounded. She wanted to say it out loud to appreciate the way it would be rolling on her tongue. She forced herself to stay quiet.

“What's yours?” Aline asked after a moment of silence.

“Why are you giving me your name?” Helen said instead.

“Why are you saving me?”

“I'm not.”

“Really?” Aline pushed on her arms to gracefully go back in the water.

Helen hadn't realized she had finally destroyed the net. When Aline saw Helen's surprised expression she smirked.

“I'm pretty sure you did.”

Helen's throat felt so dry she couldn't say a word. And then she realized what she had done. _I saved her._

“Helen, you're here?”

Helen started and immediately looked behind her. That was the voice of her mother who was probably looking for her because she'd been gone for too long. Luckily, Aline was hidden behind a rock so Helen's mother couldn't see her. But the mermaid needed to disappear quickly, she wasn't safe anymore.

Helen looked at Aline, fear in her eyes, but the mermaid smiled calmly.

“It was nice getting to know you, Helen.”

And she dived into the water.

Helen composed herself, put a neutral expression on her face and reluctantly joined her mother.

No one will ever know.

* * *

A few days had passed and Helen was finally leaving for her first hunt. She had said goodbye to her siblings, hugged her parents and all she needed to do now was to leave with her ship.

She tried to ignore the way her hands shook when she raised the sails and watched Alicante slowly disappearing as the boat distanced itself from the island.

When all she could see was the sea, she decided it was a good time to analyse the maps she'd been given. She went into her cabin, put the documents on a table and drew with a red pen the path she needed to follow. She had spent almost 18 years of her life learning every piece of these maps but some revision couldn't hurt.

She knew the way. She knew the strategy. She knew the method. She knew everything.

She just didn't know if she could do it.

Helen sighed and after peeking at her compass to make sure the boat was going in the right direction, she went back on the deck. She leaned against the railing and observed her knife once again. Her name was engraved on the blade, right under _Nerissa_ , her mother's name. She brushed the shapes of the letters with her thumb and she was about to lose herself in her thoughts when she suddenly heard a voice.

“That's a nice knife. Pretty sharp. And I can tell, I saw you using it.”

Helen jolted and turned around to see Aline right next to her, half laying on the railing.

“Sorry,” Aline apologized “I didn't mean to scare you. I've always learned to be discreet when I move and I forgot it would be better if you heard me before I just appeared out of nowhere. Well, technically not out of nowhere since I was in the water but...”

Aline seemed ready to go for a whole monologue, but Helen interrupted her. “How did you get here?”

“I climbed,” Aline answered like it was obvious.

“You often climb a boat like that? Is that a hobby or something?”

“Of course not, I just knew it was you. I saw you leaving.”

Helen raised an eyebrow. “Are you stalking me?”

Aline grimaced. “I know it looks bad, but that's not what I'm trying to do!”

“You just implied that you followed me since I left Alicante.”

“Alright, I did, but I needed to talk to you.”

“My people hunt yours. Do you really think having a chat with me is a good idea?”

Helen couldn't believe it. This mermaid was just so reckless, no wonder she'd been caught a few days ago if she tried to sympathize with humans.

Aline shook her head.“Trust my words or don't, but I never approached a human before. You were the first I've interacted with. The fishing net wasn't meant for me, the sailor just missed and I, unfortunately, happened to be nearby.”

Helen, still a little suspicious, narrowed her eyes and observed Aline. She didn't know if you could let her guard down or if she should watch Aline constantly.

“And how do I know you're not pretending to reassure me so you can grab me and drown me easily? You already tried to seduce me.”

Aline rolled her eyes and, anchoring herself with her elbows, went over to the other side of the railing, where Helen was. “First of all, I already told you I never did such a thing.”

Aline was close now, Helen could almost feel the mermaid's breath on her skin so she held hers.

“Secondly, you saved me. I'd be a terrible person if I abused your trust like that.”

Aline gazed into Helen's eyes who had lost all ability to function at this point.

“You're doing it again.” Helen stammered.

“I'm not,” Aline promised and there was innocence in her pupils, no glimpse of mischief nor mockery. So Helen trusted her. But now she was afraid of the meaning of her own behavior.

She stepped back, putting some distance between them and pretended to check where the wind was going. She needed to clear her head.

Aline just waited and when Helen noticed the mermaid hadn't moved, she sighed.

“What do you want from me?”

“I know you saved me so I'm already indebted to you...” Aline paused a few seconds. “But I need to ask you for another favour.”

Helen frowned.

“I broke my rules for you,” She snapped. “I can't do it again and help you! I was supposed to kill you, not help you escape!”

“Then kill me. Kill me and go back to your family. Everyone will be so proud of you. But for how long? You'll need to hunt again. It'll never stop. And I'm sure you don't want that.”

In a fraction of a second, Helen went back in front of Aline. “You don't know what I want.” Her voice was low, like she was containing her anger.

She was not angry at Aline. She was angry at herself. Because the mermaid could read her like an open book and Helen was scared. What if her parents knew? What if everyone knew? How could she even come back home after betraying her own kind?

Aline held Helen's gaze. “I know that you're not a murderer.”

Helen didn't answer so Aline kept going.

“And I know a way to stop everything.”

Helen's stern expression was suddenly replaced by hope. “You do?”

“Will you help me or not?”

“These hunts shouldn't exist. They're awful and inhuman. If you can really put an end to all of this then yes, I'll help.”

“Thank you.” Aline seemed relieved.

“How do we do that?”

“You should take a seat, my explanation is gonna be long. First, I need to tell you how this whole situation happened.”

Helen obeyed and sat on the floor, her back against the mat.

“Did you wonder why your people were suddenly able to see us when your island had been inhabited for centuries?” Aline asked

“I've always assumed we just never looked in the right place?”

Aline shook her head. “We've always been here, living in the sea and crossing paths with your boats. But humans couldn't find us before because a spell was hiding us.”

“What happened?”

“Your people may be cruel, but mine made a terrible mistake and we're paying the price for it. Mermaids use to play with sailors, seduce them and leave them completely disoriented. It was just a game, a bad one but they didn't mean any harm. And the sailors would never know what happened, they would just think they had drunk too much. But one day, a mermaid pushed the game too far and drowned a human.”

Aline stopped her story for a few seconds and looked at Helen to see her reaction.

“Keep going,” Helen said.

“This human was the son of a witch. When she learned the death of her beloved son, she went into a terrible rage. She broke the spell that was protecting my people and cursed us making us captive in this sea. We're not safe anymore now that humans can see and hunt us, but we can't run away.”

Helen didn't say anything for a moment, lost in her thoughts. When she spoke again, she looked revolted. “You didn't deserve such a harsh punishment. So many of your people have died. The mermaid took only one life.”

Aline agreed but it hadn't been her choice to make. “We begged the witch for forgiveness, but she didn't change her mind. She said her son was everything to her and hundreds of mermaid' lives wouldn't be enough to ease her pain.”

Helen clenched her fists. “This is so unfair.”

“We came every year, trying to ask her to mitigate the punishment and she used to refuse every time. But a few years ago, she said she would free us if we could find a pure human soul willing to save us.” Aline explained and she gazed at Helen intensively.

And then, Helen understood. “That's why you followed me all this way from Alicante? How could you know I would be the one you needed?”

“You saved me. I was immobilised and unharmed. I would've been so easy to kill, but you saved me. I'm pretty sure that's what a pure soul means.”

Helen blinked, surprised.

_She thinks my soul is pure._

_And she truly believes I'm not a killer._

Helen couldn't help but smile and Aline did the same.

* * *

The maps in Helen's cabin were long forgotten. Helen didn't want to find any mermaid to hunt, she wanted to find the little island where the witch lived. And Aline was guiding her so Helen didn't even look at a map. She just followed Aline without any hesitation.

As they were traveling, Aline told her more about the witch. Her name was Lilith, she was extremely powerful and she basically knew everything that was happening in the sea. So she definitely knew they were coming.

The journey took a few days and Helen was getting used to having Aline around. She liked talking to her, about everything but mostly about the sea. Helen had always loved the sea, but her siblings didn't share her interest so she was happy to finally have someone who understood her fascination.

She also discovered Aline loved the stars.

When it was getting late, Aline, who was exhausted after swimming all day, would join Helen on the ship. Helen would lay down beside her and they would look at the stars together. Helen would teach Aline the names of the constellations until they would both fall asleep.

Helen liked these peaceful moments. She liked waking up close to Aline and she liked watching the mermaid swimming and diving into the water. She liked to hear her beautiful laugh. She wanted Aline to be happy.

 _I think I love her_ , Helen realized when Aline turned around to smile at her after seeing Lilith's house on the horizon.

“We're almost here!” Aline said, the tone of her voice betraying her excitement.

Helen nodded. She ignored the voices telling her that her family would never approve and smiled back at Aline.

When the land was close enough, Helen dropped the anchor and went down from the ship. The water came up to her knees and she looked at Aline, who wouldn't be able to follow her.

“I guess I'm gonna go alone.”

“Please be safe.”

Helen smiled. “Why would she hurt me?”

“Right, why would I?”

Helen, who hadn't expected Lilith to appear right behind her, jolted. She turned to face Lilith and placed herself in front of Aline just in case.

Lilith laughed. “Trying to defend your precious little mermaid? Cute.”

Aline put a hand on Helen's arm and gently pushed her aside. “It's okay, Helen.”

Helen bit her lips. _No, it's not. I don't want you to be hurt._

“I actually never thought you would come back with a human one day,” Lilith admitted. “I thought you would all just die trying because you were so desperate.”

Lilith looked at Helen like she was trying to read her deepest thoughts. Helen shivered and immediately broke eye contact. That just amused Lilith.

“I guess some humans can still surprise me after all.”

Aline found the strength to remind Lilith of their agreement. “You promised you would break the curse if a human with a pure soul asked you to do so.”

“Do you believe her soul is pure?”

“I do, with all my heart.”

“We'll see if you're right.”

Without a warning, Lilith twisted her wrist and Helen who had suddenly lost control of her own body, arched her back. She felt like Lilith was pulling something out of her chest. It wasn't painful. It was just cold, so so cold. Helen had the impression she was completely frozen. Aline screamed something, but Helen couldn't hear it, Aline's voice was so far away.

Then it all stopped. Helen's legs gave out and Aline caught her before she hit the ground. Helen was still shaking from the cold so Aline hugged her tightly.

“I'm sorry. I'm so sorry.” Aline couldn't stop apologizing. “I had no idea she would do that to you.”

Helen wanted to say she was okay, but no word passed her lips. She was just so tired. She rested her head against Aline's shoulder and she immediately felt Aline's warm hands brushing her cheeks. She sighed deeply.

“Are you alright?” Aline asked and Helen nodded.

“Interesting. Very interesting.” Lilith said and the attention was focused on her again.

The witch was looking at a little light pulsing and glowing in the palm of her hand. Helen frowned.

“What... Is that?”

“Your soul,” Lilith answered like it was nothing “Well, a piece of it. And I can confirm yours is perfect for what I need.”

Helen didn't understand. Perfect for what?

“You never mentioned you would steal the soul of the human.” Aline accused Lilith who looked offended.

“Well, you never asked. And I'm just taking a small part of it, she won't notice the change.

“Why do you need it?”

Lilith seemed to be exhausted by Aline's incessant questions, but probably feeling generous, she answered. “The sea took the soul of my son. I'm giving her another soul so I'll have my son back.”

Helen didn't know what she should think about that. “What will happen to me?”

Lilith didn't even look at her, entirely focused on the fragment of soul she was holding. “You're not going to die if that's what you're asking.”

“Amazing,” Helen huffed “Can you be more specific maybe? I mean, that's my soul."

“Your soul will be linked to the sea.”

“What does it mean?”

Lilith smirked. “You'll find out soon.”

Helen, who had now recovered from the “losing a part of her soul” experience, stood up.

“Let's do this.” Her voice was no longer trembling.

Helen was about to take a step in Lilith's direction, but Aline stopped her by taking her hand.

“You don't have to do this.” Her tone was suppliant.

Helen couldn't help but intertwine their fingers together. “I want you and your people to be safe.”

“But I also want you to be safe,” Aline said, almost begging now.

Helen blinked. She was speechless. Aline cared for her. Helen's people were hunting the mermaids, but Aline cared for her.

_Why does that make me feel so happy?_

Aline shook her head. “Please, don't sacrifice yourself for me.”

Helen blinked back the tears threatening to flow and tenderly gazed at Aline. “I'll be okay.”

“Please-” Aline started, but Lilith, who was losing her patience interrupted her.

“Are you two having a romantic moment? Should I just leave you both alone so you can stare at each other and kiss dramatically?”

There was a moment of silence. Helen raised an eyebrow. _Can I?_

Aline chuckled and put her arms around Helen's neck, forcing her to lean down. Helen took that as a yes and so, she kissed Aline.

It was gentle, soft and calm. It was just so peaceful, so obvious and Helen felt so loved. She smiled against Aline's lips and Aline kissed her back.

“Oh my god,” Lilith rolled her eyes. She was so done with them. “I was being sarcastic. That wasn't an invitation.”

Helen stepped away reluctantly, but she didn't let go of Aline's hand. She took a deep breath and looked at the witch.

“Break the curse and then you can use my soul to bring back your son.”

Satisfaction appeared on Lilith's face. She closed her eyes and started an incantation.

As she was reciting the spell, dark clouds were invading the sky and the wind was getting stronger. And the more she used her magic, the more the storm raged on.

Lilith said more words in a language Helen didn't understand. There was thunder now, the weather kept getting worse.

Helen felt numb, it was like her feet weren't touching the ground anymore. Then she realized it wasn't just an impression. She was being dragged to the centre of the storm.

She heard Aline screaming her name and then nothing. Everything went dark.

* * *

Helen woke up in a room. Her room. She was back in Alicante. Was everything just a dream?

“You're finally awake!”

Helen turned her head and saw her mother, sitting on a chair next to her bed. Nerissa smiled and put her palm on Helen's forehead, checking her temperature.

Helen was confused. How did she end up here? She sat up and winced. Her head was hurting so much.

“Hey,” Her mother scolded her gently and forced her to lay down “Be nice to your body. You've been through a lot.”

“What happened?”

“You don't remember?”

“The last thing I remember is me looking at the maps in my cabin.” Helen lied.

“There was an awful storm, you were probably on your way back because your boat crashed not far from the island. We found you unconscious on the beach.”

“I crashed the boat?” Helen faked her panic. “Oh no, mum, I am so sorry I...”

“It's okay sweetheart, the wind was so powerful and the waves so high, there was nothing you could have done. It's already a miracle that you got out of it alive.”

Helen had the impression she knew the name of that miracle.

“How long have I been unconscious?”

“Three days. Your father wanted to make you travel with the others, but I said you needed to rest.

Helen sat up again, ignoring her headache. “Wait, slow down. Travel where?”

“It's probably because of the storm, but the mermaids are gone.”

“Gone,” Helen repeated, trying to hide the joy this news brought her.

“We searched everywhere but we couldn't find them,” Nerissa explained “They're gone. Your father thinks they probably went to the north, so he decided we should move there. He left yesterday with your siblings. If we travel fast, we'll join them on the road soon enough.”

Helen didn't say anything so her mother started to worry.

“What's wrong?”

“I don't want to go.”

Nerissa frowned, surprised by this answer. “Why?”

“I want to stay here. I feel like I belong here.”

Helen looked so certain, so determined, her mother realized nothing would make her change her mind.

“Is that really what you desire?”

Helen nodded. “I know where my place is.”

Nerissa seemed somehow proud of her daughter. She smiled and invited Helen for a hug. Helen immediately accepted and they shared one last moment together.

* * *

Helen was facing the sea. She was alone now, all her family had left, but she had decided to stay. But she wasn't sad. It wasn't the end. Only the beginning of everything. And Helen didn't regret anything.

She took her shoes and her clothes off, then slowly entered into the sea. The sensation was amazing and Helen hummed in satisfaction.

When the water was deep enough, she breathed one last time and then she immersed herself entirely. She started swimming and she kept going deeper and deeper. She felt her body changing and she lowered her gaze. Her legs were slowly being replaced by a long red tail. She was a mermaid now.

Someone called her name, Helen looked up and Aline was there, smiling and waiting for her with open arms.

_That's where I belong._

> _I'm not afraid_
> 
> _Because I'm not alone._
> 
> _She's waiting there_
> 
> _To carry me home._
> 
> _I'm coming home._
> 
> _Dead Man’s Eyes, Apocalyptica_

**Author's Note:**

> Thanks for reading!
> 
> If you enjoyed, don't forget to let a comment and/or a kudo :)
> 
> You can find me on twitter ! (@Onceuponavideo1)
> 
> Special thanks to @randomrambler who beta read this fic! (thank you thank you thank you)


End file.
